1. Field of the Invention
The present invention generally relates to an apparatus for converting an Internet protocol address for exclusive use in a home network system and a home network system using the same, and more particularly, the present invention relates to an apparatus for converting an Internet protocol address for exclusive use in a home network that is capable of providing a service for achieving a communication between an IPv4 terminal using an Internet Protocol version 4 (IPv4) as a communication protocol and an IPv6 terminal using Internet Protocol version 6 (IPv6) as a communication protocol, and a home network system using the same. This application claims priority from Korean Patent Application No. 2002-0005227, filed on Jan. 29, 2002, which Korean Application is incorporated herein in full by reference.
2. Description of the Prior Art
Internet Protocol (IP) is one of the most generally known protocols used for the network layer of TCP/IP communication. The IP is the addressing service provided by a network layer of third layer of Open Systems Interconnection model, which designates a plurality of nodes connected to the network as a destination to perform communication. Among the IPs that are currently available, the most popular one is the Internet Protocol version 4 (IPv4). The IPv4 uses an IP address of 32 bits.
With the ever-growing number of users, computers are now becoming a necessity in people's daily lives. The number of addresses of Internet users has been exploding, while the IPv4 IP address format of 32 bits hardly satisfies such continuously growing demands. In an attempt to solve this problem, IPv6 has been developed by the Internet Engineering Task Force (IETF) as the next generation Internet Protocol.
The IPv6 uses the address format of 128 bits. The IPv6 not only extends the number of IP addresses, but also reduces costs for broadband width and processing of a common header, as it is capable of simplifying the common header format. Also, by adopting a concept of ‘flow label,’ IPv6 enables efficient real-time processing of multimedia data. Moreover, the IPv6 provides much strengthened security functions like verification, faultless data, airtight data, etc.
The Internet communication infrastructure used for the IPv4 is also used for the IPv6. Accordingly, in order to accomplish a communication between the IPv4 terminal and the IPv6 terminal, an IPv4-IPv6 converter that connects the IPv4 net and the IPv6 net is necessary.
FIG. 1 is a block diagram showing network system using a conventional IPv4-IPv6 converter. Referring to FIG. 1, conventionally, the IPv4 network 20 and the IPv6 network 40 are connected by the IPv4-IPv6 converting device 10. The IPv4 network 20 is connected with an IPv4 terminal 31, a domain name service version 4 server (DNSv4) 33, and a dynamic host configuration protocol version 4 server 35 (DHCPv4). The DNSv4 server 33 manages the domain name information within the IPv4 network 20. The DHCPv4 server 35 dynamically allots the IPv4 address to the IPv4 terminal 31 that is connected to the IPv4 network 20.
The IPv6 network 40 is connected to an IPv6 terminal 51, a DNSv6 server 53 and a DHCPv6 server 55. The DNSv6 server 53 manages the domain name information within the IPv6 network 40. The DHCPv6 server 55 dynamically allots the IPv6 address to the IPv6 terminal 51 that is connected to the IPv6 network 40.
The communication operation between the IPv4 terminal 31 and the IPv6 terminal 51 will be described below.
First, the IPv4 terminal 31 makes a query to the DNSv4 server 33 for an IPv4 address that corresponds to the domain name of the IPv6 terminal 51. The DNSv4 server 33 provides the IPv4-IPv6 converting device 10 with the information about the requested IPv4 address that corresponds to the domain name of the IPv6 terminal 51. The sender address is the IPv4 address of the DNSv4 server 33, while the destination address is the IPv4 address of the IPv4-IPv6 converting device 10. The IPv4-IPv6 converting device 10 converts the IPv4 address of the sender, i.e., of the DNSv4 server 33 into the IPv6 address. At this time, the IPv4-IPv6 converting device 10 converts the IPv4 address of the DNSv4 server 33 into the IPv6 address by adding a prefix to the IPv4 address of the DNSv4 server 33. The IPv4-IPv6 converting device 10 also has the IPv6 address of the DNSv6 server 53 that manages the domain information of the terminal like the IPv6 terminal 51 that is connected to the IPv6 network 40. Accordingly, the IPv4-IPv6 converting device 10 is connected to the DNSv6 server 53 and requests the IPv6 address corresponding to the domain name of the IPv6 terminal 51. The sender address is the IPv6 address of the DNSv4 server 33, while the destination address is the IPv6 address of the DNSv6 server 53.
The IPv6 address corresponding to the domain name of the IPv6 terminal 51 being requested, the DNSv6 server 53 extracts the IPv6 address from a stored table and provides the IPv4-IPv6 converting device 10 with the extracted information. The IPv4-IPv6 converting device 10 converts such received IPv6 address of the IPv6 terminal 51 into the IPv4 address, and provides the DNSv4 server 33 with such converted IPv4 address of the IPv6 terminal 51. The DNSv4 server 33 provides the IPv4 terminal 31 with such received IPv4 address of the IPv6 terminal 51. Accordingly, the IPv4 terminal 31 is enabled to find out the IPv4 address that corresponds to the domain name of the IPv6 terminal 51.
Provided with the IPv4 address corresponding to the domain name of the IPv6 terminal 51, the IPv4 terminal 31 sends a communication request signal with the IPv6 terminal 51 to the IPv4-IPv6 converting device 10. The sender address is the IPv4 address of the IPv4 terminal 31, while the destination address is the IPv4 address of the IPv6 terminal 51. When the IPv4 terminal sends the control information to the terminal in the IPv6 network 40, a mapping table within the converting device 10 is searched. If there is an IPv6 terminal 51 registered for the IPv4 address, i.e., the destination address, there is no need to perform the converting process additionally. With the address of IPv6 system with respect to the IPv4 terminal 31 and the IPv6 terminal 51, the IPv4-IPv6 converting device 10 sends a connection request signal from the IPv4 terminal 31 to the IPv6 terminal 51. With the address conversion by the IPv4-IPv6 converting device 10, the IPv4 terminal 31 and the IPv6 terminal 51 communicates with each other.
FIG. 2 is a view showing one example in which the network system using the IPv4-IPv6 converting device 10 of FIG. 10 is used in the home network system. The IPv4-IPv6 converting device 10 as used in the home network is called a home-only IP address converting device. However, it will be understood by those of ordinary skill in the art that the devices, systems and methods disclosed herein are not restricted to use In a home. Rather, what is intended is any application, including an office, vehicle, school, or other such environment, for which the devices, systems and method herein disclosed are suitable.
Hereinbelow, the communication operation between the IPv4 terminal 31, namely, a personal computer 31a and a refrigerator 31b and the IPv6 terminal 51, namely, a digital television 51a and a laptop computer 51b. 
Based on the services provided by the DNSv4 server 33 and the DHCPv4 server 35, the personal computer 31a and the refrigerator 31b perform a communication with the devices within the IPv4 network 20a. Also, based on the services provided by the DNSv6 server 53 and the DHCPv6 server 55, the digital television 51a and the laptop computer 51b perform the communication with the devices within the IPv6 network 40a. 
Meanwhile, in order to achieve a home networking among the communicable devices within the home network, the home network system is provided with a master server 37. The master server 37 manages and registers the registration information of the devices of the home network. The registration information may not necessary include additional information about IP address, as it will become known through a FPC communication.
The conventional home network system requires the IPv4-IPv6 converting device 10 that provides a converting service of converting the IP address formats for a communication between the IPv4 terminal 31 and the IPv6 terminal 51. By the services provided by the IPv4-IPv6 converting device 10, communication among the personal computer 31a and the refrigerator 31b, and the digital television 51a and the laptop computer 51b is enabled. In order to apply the IPv4 terminal 31 and the IPv6 terminal 51 in the home network system, the home network requires the DNSv4 server 35 and the DHCPv4 server 35 that provide the IPv4 terminal of the home network with the IP address and the domain name, and also the DNSv6 server 53 and the DHCPv6 server 55 that provide the IPv6 terminal of the home network with the EP address and the domain name, which generates inconvenient jobs such as system establishment, etc.
There is another problem that the services of the DNSv6 server 53 and the DHCPv6 server 55 become redundant with respect to the services of the DNSv4 server 33 and the DHCPv4 server 35. Also, in order for the IPv4 terminal 31 and the IPv6 terminal 51 to communication with each other, the IPv4 terminal 31 and the IPv6 terminal 51 have to use the services of the DNSv4 server 33 and the DHCPv4 server 35 and the DNSv6 server 53 and the DHCPv6 server 55. Accordingly, communication among the IPv4 terminal 31 and the IPv6 terminal 51 sometimes causes overload in the operation of the respective servers 33, 35, 53, 55.
Also, since the conventional home network requires the installation of all of the DNSv4 server 33, the DHCPv4 server 35, the DNSv6 server 53 and the DHCPv6 server 55 therein, a problem of taking too much space arises.